Apparatus for the treatment of freshly spun spandex thread



Aug? 4,1970 H. K. BARKER 3,522,698

APPARATUS FOR THE. TREATMENT OF FRESHLY SPUN SPANDEX THREAD Filed June 4, 1968 lnugnlor HARRY KEITH BARKER y DAVIS, HOXIE, FAITHF L 86 HAPGOOD llornel United States Patent 3,522,698 APPARATUS FOR THE TREATMENT OF FRESHLY SPUN SPANDEX THREAD Harry Keith Barker, Kenilworth, England, assignor to Courtaulds Limited, London, England, a British company Filed June 4, 1968, Ser. No. 734,438 Claims priority, application Great Britain, June 15, 1967, 27,678/ 67 Int. Cl. D01h 7/92 US. Cl. 57-77.4 7 Claims ABSTRACT OF THE DISCLOSURE Apparatus for the treatment of a freshly-spun spandex multifilament thread comprising a rotatable thread-advancing device, for example a thread-advancing reel, a cowl mounted at the end of the device from which the thread is advanced and rotatable with the device, the cowl encircling the device at that end and presenting an annular smooth surface for contacting a thread which is passing onto the device when the device and cowl are rotating, so as to twist the thread, and a thread guide located between the cowl and the device for maintaining the thread in running contact with the smooth surface of the cowl. The thread guide may be a curved rod which extends into the space between the cowl and the thread advancing device.

This invention relates to the production of artificial fibres and is particularly concerned with the production of spandex filaments by a process in which a precursor of the spandex filament, that is to say a polyesteror a polyether-polyisocyanate reaction product, is extruded through a multi-hole spinning jet into a coagulating bath containing a poly-functional reagent, for example a diamine such as ethylene diamine, which is capable of reacting with the precursor to form filaments of the spandex type.

The freshly-formed filaments after they have been withdrawn from the coagulating bath require further processing for example to allow the reaction to go to completion and to wash off excess reagents; one or more stretching steps may also be introduced during the processing stages. Such processing may conveniently be effected while the filaments are passed over a series of thread advancing devices such as reels or rollers and drying of the final washed product may also be accomplished on a heated thread-advancing device. It is usually so arranged that, during the processing, the filaments fuse together to form an effective monofilament.

It has been found that when a bundle of freshlyf formed spandex filaments is passed from the coagulating bath directto a thread-advancing device, particularly of the reel type, there is a tendency for the fflaments to become flattened out into a tape with the result that in the final product the filaments are more or less fused together to form a roughly rectangular-shaped cross-section rather than a circular cross-section which is generally preferred.

In British patent specification No. 653,363 it has been proposed in wet spinning generally, and in viscose spinning specifically to pass the wet spun thread, as it is withdrawn from the coagulating bath and passed to a rotating take-up device, directly against the edge of a smooth annular guid rotating at a peripheral speed greater than the peripheral speed of the take-up device. The smooth annular guide, which acts as a false-twisting device, may conveniently take. the form of a cowl which is fitted to and surrounds the receiving end of the take-up device.

However, the application of the apparatus described in the above-mentioned British patent specification No. 653,363 to the spinning of a spandex multifilament thread has proved unexpectedly ditficult, because the elasticity of such threads causes them either to mount up onto the peripheral surface of the cowl or to come away from it intermittently as a slip-stick motion occurs between the thread and the annular guide.

According to the present invention apparatus for the treatment of a freshly-spun spandex multifilament thread comprises a rotatable thread-advancing device, a cowl mounted at the end of the device from which the thread is advanced and rotatable with the device, the cowl encircling the device at that end and presenting an annular smooth surface for contacting a thread which is passing onto the device when the device and cowl are rotating, so as to twist the thread, and a thread guide located between the cowl and the device for maintaining the thread in running contact with the smooth surface of the cowl.

The thread-advancing device may with advantage be a thread-advancing reel, and the thread guide for maintaining the thread in running contact with the cowl may conveniently take the form of a curved rod extending into the space between the reel and the cowl, being curved so as to extend substantially degrees around the reel. If desired, an auxiliary guide may be included to prevent the thread from being carried over onto the peripheral surface of the cowl but we prefer that the cowl has an annular bevel adjacent to the annular smooth surface and radially outwardly of it. A further bevel, radially inwardly of the smooth annular surface, may also be provided so as to minimise any tendency for the thread to be flattened as it passes from that surface towards the thread guide.

According to a further aspect of the invention a process for the production of a multifilament spandex thread comprises extruding a solution of a precursor of the spandex filament into a coagulating bath which is capable of reacting with the precursor to form filaments of the spandex type, withdrawing the thread upwardly from the bath onto a rotating thread-advancing device by way of a smooth annular surface on a cowl which is mounted at the end of the thread advancing device from which the thread is advanced and rotatable with the device, so that the thread is twisted, in which the thread is passed around a guide located between the cowl and the threadadvancing device so as to maintain the thread in contact with the smooth annular surface of the cowl.

A preferred embodiment of apparatus in accordance with the invention will now be described, by way of example, with reference to the accompanying drawing, in which FIG. 1 is a schematic end elevation of the apparatus, and

FIG. 2 is a schematic side elevation of the apparatus.

Referring to the drawing, a thread-advancing reel 1 has a cowl 2 at the end from which the thread is advanced. The cowl 2 incorporates a smooth annular surface 3 against which a thread 4 is contacted before it is taken up on the reel. Between the cowl 2 and the reel 1 is a curved rod 5 which maintains the thread 4 in contact with the smooth annular surface 3. The curved rod 5 is supported at one end by a mounting assembly 6 which is attached to the spinning machine (not shown). The reel 1 and the cowl 2 are mounted on a shaft 7 which in turn is mounted on, and rotated by, the spinning machine. The smooth annular surface 3 is bevelled radially outwardly as shown at 8 and radially inwardly as shown at 9. The arrows indicate the direction of rotation of the reel 1 and cowl 2, and the direction of travel of the thread 4.

3 The following example illustrates the results obtained using apparatus substantially as described above with reference to the drawing.

EXAMPLE A polyester resin, a condensation product of ethylene glycol, propylene glycol and adipic acid, was reacted with p-p'-diphenyl methane diisocyanate to form the polymeric spandex precursor containing isocyanate groups. The polymer was extruded into a bath of percent by weight of ethylene diamine in isopropyl alcohol at C. The jet had holes of 0.1016 mm. diameter and was 9.5 mms. below the bath surface, and excess spin bath was scraped from the thread by passing it through a guide consisting of two inclined ceramic rods about 2 to 8 cms. above the bath surface. The thread was wound at 44 metres/minute onto a thread-advancing reel after first being twisted by the cowl and guide assembly as described above with reference to the drawing. The thread was allowed to dwell on the reel for about 1 minute to complete the fixing and fusing of the thread.

The thread was then stretched 85 percent onto a second reel where it was washed for 1 minute with hot water, and washing was continued on further reels.

The thread then passed to a drying reel where the imparted stretch was heat-set for about 2 minutes, and then the thread was allowed to relax onto the take-up package.

The extent to which the cross-section approaches a true circle can be conveniently expressed as the Flatness ratio (i.e. the ratio of the longest and shortest axis across the cross-sectional shape). A high figure for flatness ratio means a flat yarn whilst a figure of 1 would represent a completely circular yarn.

Very good. 2 Fair.

What is claimed is:

1. Apparatus for the treatment of a freshly-spun spandex multifilament thread comprising a rotatable threadadvancing device, a cowl mounted at the end of the device from which the thread is advanced and rotatable with the device, the cowl encircling the device at that end and presenting an annular smooth surface for contacting a thread which is passing onto the device when the device and cowl are rotating, so as to twist the thread, and a thread guide located between the cowl and the device for maintaining the thread in running contact with the smooth surface of the cowl.

2. Apparatus as claimed in claim 1 wherein the thread-advancing device is a thread-advancing reel.

3. Apparatus as claimed in claim 1 wherein the thread guide is a curved rod which extends into the space between the cowl and the thread advancing device.

4. Apparatus as claimed in claim 3 wherein the curved rod extends substantially degrees around the device.

5. Apparatus as claimed in claim 1 wherein the annular smooth surface of the cowl is in a plane which is substantially at right angles to the axis of rotation of the cowl.

6. Apparatus as claimed in claim 5 wherein the cowl has an annular bevel adjacent to the annular smooth surface and radially outwardly of that surface.

7. Apparatus as claimed in claim 6 wherein the cowl also has an annular bevel adjacent to the annular smooth surface and radially inwardly of that surface.

References Cited UNITED STATES PATENTS 2,988,867 6/1961 Quittner 5777.4 XR 3,091,075 5/1963 Hamilton 5732 3,094,834 6/1963 Deeley et al. 5777.4 XR 3,156,084 11/1964 Van Dijk et al. 5777.4 3,296,786 1/1967 Wyatt S777.4 XR

STANLEY N. GILREATH, Primary Examiner W. H. SCHROEDER, Assistant Examiner 

